My answer is based upon Utah law because I practice divorce and family law in Utah.

Currently in Utah about the fastest period of time in which to obtain a court order for child support on a temporary orders basis while waiting on the court to issue a final permanent order is about a month, if you play your cards right. Now remember, this is the fastest, not the usual, period of time one could expect in Utah. The average period of time, if you’re doing your best to move the process along and you have a cooperative court? I’d say about 2–3 months, depending upon how antagonistic the opposing party and his/her lawyer (if any) are. If you want me to go into the procedural details as to how and why, just ask me on Quora, and I’ll happily answer that separate question.

If you’re interested in how to obtain an administrative child support order through Utah’s Office of Recovery Services, you may find this helpful: Establishing a Child Support Order Through the ORS Administrative Process